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In terms of environmental factors, dietary salt intake is the leading risk factor in the development of hypertension. [7] Salt sensitivity is characterized by an increase in blood pressure with an increase in dietary salt and is associated with various genetic, demographic, and physiological factors— African American populations, postmenopausal women, and older individuals carry a higher ...
More recent MRI studies have reported age-related regional decreases in cerebral volume. [6] [7] Regional volume reduction is not uniform; some brain regions shrink at a rate of up to 1% per year, whereas others remain relatively stable until the end of the life-span. [8]
The brain volume decreases roughly 5% per decade after forty. It is currently unclear why brain volume decreases with age. However, a few causes may include cell death, decreased cell volume, and changes in synaptic structure.
For example, an increase in lesion volume (e.g., epidural hematoma) will be compensated by the downward displacement of CSF and venous blood. [24] Additionally, there is some evidence that brain tissue itself may provide an additional buffer for elevated ICP in circumstances of acute intracranial mass effect via cell volume regulation. [25] [26]
The cerebral blood volume value of gray matter is about 3.5 +/- 0.4 ml/100g, and the white matter is about 1.7 +/- 0.4 ml/100g. The gray matter is nearly twice that of white matter. [3] In both white and gray matter, cerebral blood volume decreases by about 0.50% per year with increasing age. [4]
Following extended sobriety, the volume of the lateral and third ventricles was decreased, and abstainers showed an improvement in working memory and balance. [16] Finally, evidence for the recovery of brain volume with continued sobriety is supported by the improvement in neuropsychological performance.
An alternative definition of CPP is: [1] = where: MAP is mean arterial pressure ICP is intracranial pressure JVP is jugular venous pressure. This definition may be more appropriate if considering the circulatory system in the brain as a Starling resistor, where an external pressure (in this case, the intracranial pressure) causes decreased blood flow through the vessels.
Hypertensive encephalopathy (HE) is general brain dysfunction due to significantly high blood pressure. [3] Symptoms may include headache, vomiting, trouble with balance, and confusion. [1] Onset is generally sudden. [1] Complications can include seizures, posterior reversible encephalopathy syndrome, and bleeding in the back of the eye. [1] [3]